[1/5] x86/cpu: Add a steppings field to struct x86_cpu_id

[1/5] x86/cpu: Add a steppings field to struct x86_cpu_id

Origin: https://git.kernel.org/linus/e9d7144597b10ff13ff2264c059f7d4a7fbc89ac
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2020-0543

Intel uses the same family/model for several CPUs. Sometimes the
stepping must be checked to tell them apart.

On x86 there can be at most 16 steppings. Add a steppings bitmask to
x86_cpu_id and a X86_MATCH_VENDOR_FAMILY_MODEL_STEPPING_FEATURE macro
and support for matching against family/model/stepping.

 [ bp: Massage.
   tglx: Lightweight variant for backporting ]

Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Gbp-Pq: Topic bugfix/x86/srbds
Gbp-Pq: Name 0001-x86-cpu-Add-a-steppings-field-to-struct-x86_cpu_id.patch